Patent GB-599726-A (GB)
Title: Improvements in and relating to x-ray apparatus
IPC: H05G1/04
Filed: 1943-10-18
Abstract: 599,726. X-ray tubes. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 18, 1943, No. 17065. Convention date, Oct. 22, 1942. [Class 39 (i)] [Also in Group XX] X-ray apparatus comprises a sealed casing forming a compartment containing an X-ray tube resiliently supported therein and electrically insulated therefrom by means comprising synthetic rubber material and surrounded by a gaseous insulating medium, such as a halogen derivative of an aliphatic hydrocarbon, adapted to be delivered into or displaced from the compartment through means located in either or both of two end coverplates attached to the casing, storage means for the gaseous insulating medium being attached to one end cover-plate and connected with and thermally insulated from the compartment to maintain a constant pressure therein. As shown in Fig. 2, the housing 11 contains an X-ray tube 13 comprising a rotating anode 15 and a cathode 17 mounted within a sealed envelope 19. An anode connection 21 and filament conductors 25 are provided. The anode may be rotated by the motor 27. The housing 11 has an opening 33 provided with an annular collar 35 forming an outwardly extending hood, and is closed by a cup-shaped plate 37. The housing 11 I is provided on the opposite side with chambers 43, 44 closed at one end and open at the other to receive cable terminals. The ends of the housing 11 are closed by plates 59, 60. The bracket 65 attached to lug 63 of the housing 11 has a circular aperture receiving a resilient neoprene disc, to which is secured by a bolt a moulded insulating bracket 85 carrying the anode connection 21. The cathode end of the tube is supported by a metal bracket 95 carrying a resilient neoprene disc having a central opening receiving the end of the cathode stem 29. A central opening in the cover-plate 59 is closed by a threaded plug 115, and a central opening in the cover-plate 60 is closed by a threaded fitting 119 having an opening containing a valve comprising a spring-pressed ball and closed by a threaded plug. The housing 11 may be charged with dichlorodifluoromethane or dichlorotetrafluoroethane through the valve in fitting 119, the plug 115 being removed to allow escape of displaced air. Alternatively, the air may be exhausted from the casing by connection of an exhaust pump to a threaded port 141 communicating through the duct 139 with the opening 137 adapted to be closed by the plug 115. The fitting 119 may be kept closed or replaced by a solid plug and the exhausting and charging effected entirely through the duct 139. An auxiliary casing 143, Fig. 6, may be provided with a pipe 145 adapted to be secured in the boss 113 of the cover-plate 60, the other end of the pipe 145 extending within casing 143 to form a liquid trap preventing passage of liquid to the casing 11. The casing 143 is fitted with a charging opening 147 closable by a plug 149 carrying a valve member 151 controlling gas flow through the pipe 145. The pipe 145 is of non-conducting material to thermally insulate the casing 143 from the casing 11. Specifications 555,013, [Group XX], and 557,631 are referred to.